In the board game “So Many Bills”, there are $1, $2 and $3 bills.
There are 11 more $2 bills than $1 bills.
There are 18 fewer $3 bills than $1 bills.
If there is $100 in total, then how many $1 bills are there in the board game?
We're going to turn each sentence into an equation.
a = number of $1, b= number of $2, c= number of $3
b=a+11
c=a-18
a+2a+3b=100
Substituting the first two equations into the third equation,
a+2a+22+3a-54=100
Simplifying, we get 6a=132, a=22
So there are 22 one-dollar bills.